Arshi, pls bear with me as the comments I am going to write below are more of my running thoughts. I have been thinking of this question ever since we had the discussion last time.
If we see any movie or show adapted from a book, the procedure I think is almost the same. When a producer buys the right to adapt a book for sometime, the two parties here are the producer and the author.
If we see from the author's perspective, is it a good experience having his book adapted, that too by a big producer ? The answer is Yes, one is financial benefit. He receives royalties with almost no extra work.And for many a book adapted for a TV show, is a great exposure and recognition that his book gets, that he himself receives. Tell me frankly, how many of us have heard of the novel "Saraswathichandra" before SLB came up with the show ? I haven't, it was only after he started the promotion of the show I digged up wiki of the book and started browsing around for more information. Isn't that a publicity for the author and the book, which most unknown to many. This might even help the book getting revived in this era, who knows.
Now about the license of a remaker with the original, as far as I know any author who knows the industry would be aware that adaptation of his book is not without dangerous risks.It is not the first time any book has been adapted and made into a film and the risks can be anything like dialogues not written properly, lack of understanding of the book or absurd picturisation etc. I think when a producer adapts the book, he has license to change it accordingly with the media, with the likes of the audience rather than stick to the original. I will just go with one example, one of my favourite thrillers, The Relic, killed off a character that was actually to be a main antagonist in the novel. I think it depends on perspective, if the goal is to share a story or the characters to the audience, then a screen adaptation is the best way and seeing SLB's work I have always felt that is what he wants to do. He tries to bring to screen the best forgotten historical stories and the younger generation who have never read the sequel or won't ever do atleast will be aware that something as this existed. I think I have deviated myself from the question, so as for my POV..the remaker has plenty of license to deviate from the original. I think the purits have to come to terms with the fact that every scene of a book cannot be copied into a movie or a show. If we have different perspective of a single scene in the forum, even reading a book might have a different intepretation/perspection of the story and the characters.So why doesn't SLB have the license to show his intepretation and inorder to meet the media demands,the satisfaction of the current audience and the TRP's we all have to agree that he needs to add the right amount of spices to make his show running. I am sure the author understands it, otherwise he would never have parted with his work.
As for your second question, I was thinking the same when @hotdogg gave us the details of the novel. As far as I can understand it depends on the individual SLB. If we see his work every single project of his has been huge and on different topics. He might be a man who has a vision to see a work he likes brought alive and as far as I have seen his movies he does justice to the work making it unique.Now this show is his first venture into TV, so surely has the disadvantages.Making a movie and a TV show are quite different but as I read somewhere he wanted to experiment on it and it depends if he will succecced or not. But without trying how will he know. As for choosing a story like SC,he had told in one of his interviews that he wanted to make this into a movie but since the sequel is so huge he felt inorder to do justice to the whole novel it would be better to make it into a TV show. The show can base the characters and the synopsis of the novel but can't be made the same as the original. It is not a different story altogether, we are still getting the story of SC in love with Kumud,a step mom who was supposed to be evil and the two families who seem to have a story to tell. If Kumud marries another man, then the synopsis of the story is completely there. It is only that for a screen adaptation which is needed for current audience there needs to be added masala.
It is completely my POV, I am sure many would disagree on this but inorder to find a right balance between the novel and the media, deviations from the original are absolutely necessary and it has always been that way as far as I know.